Proceedings published in International Journal of Computer


Download Proceedings published in International Journal of Computer


Preview text

International Conference on Recent Advances and Future Trends in Information Technology (iRAFIT2012) Proceedings published in International Journal of Computer Applications® (IJCA)

Design of Single Band Rectangular Patch Antenna for WLAN Application

Neha Ahuja
Student Department of Electronics & Communication Engineering Thapar University, Patiala,
Punjab

Rajesh Khanna
Professor Department of Electronics & Communication Engineering Thapar University, Patiala,
Punjab

Jaswinder Kaur
Lecturer Department of Electronics & Communication Engineering Thapar University, Patiala,
Punjab

ABSTRACT
A microstrip patch antenna for WLAN application is proposed. The antenna has a frequency bandwidth of 196 MHz (5103MHz - 5300 MHz). The microstrip antenna has a planar geometry and consists of a ground, a substrate, a patch and a feed. The basic theory and design are analyzed, and simulation using CST Microwave Studio commercial software is employed to optimize the antenna's properties. Results show that the proposed antenna has promising characteristics for WLAN application at 5.21 GHz frequency.
General Terms
Microstrip line feed, single frequency.
Keywords
Microstrip Antenna, WLAN Communication Standard, CST Microwave Studio.

1. INTRODUCTION

The microstrip antenna have a number of useful properties

such as small size, low-cost fabrication, low profile, light

weight, conformability, ease of installation and integration

with feed networks but one of the serious limitations of these

antennas have been their narrow bandwidth characteristics as

it limits the frequency ranges over which the antenna can

perform satisfactorily. These features are major design

considerations for practical applications of microstrip

antennas.

Recent technologies enable wireless

communication devices to become physically smaller in size.

Antenna size is obviously a major factor that limits

miniaturization. With the rapid growth of the wireless mobile

communication technology, the future technologies need a

very small antenna.

Wireless local area network (WLAN) and Worldwide

Interoperability for Microwave Access (Wi-MAX) technology

is the most rapidly growing area in the modern wireless

communication [1]. This gives users the mobility to move

around within a broad coverage area and still be connected to

the network. This provides greatly increased freedom and

flexibility. For the home user, wireless has become popular

due to ease of installation, and location freedom. Naturally,

these applications require antennas. This being the case,

portable antenna technology has grown along with mobile and

cellular technologies. It is important to have the proper

antenna for a device. The proper miniaturized antenna will

improve transmission and reception, reduce power

consumption, last longer and improve marketability of the

communication device. In this paper, a single band microstrip

patch antenna for WLAN application is designed and

simulated using CST Microwave Studio [4]. The proposed

patch antenna resonates at 5.21 GHz frequency.

2. GEOMETRY OF MICROSTRIP

PATCH ANTENNA

In this antenna, the substrate has a thickness h=1.6 mm and a

relative permittivity εr = 4.4. The length and width of patch are L=12.636 mm and W=25.8 mm respectively. The length

and width of ground are L=22.83 mm and W=27.154 mm

respectively. Edges along the width are called radiating edges

and that along the length are called non radiating edges [2].

It can be fed by different methods like microstrip line feed,

coaxial probe feed, aperture coupling, electromagnetic

coupling and coplanar waveguide (CPW). In this work,

microstrip line (50 ohm) feed has been used. Antenna is

designed for a resonating frequency of 5.21 GHz and is

analyzed using CST Microwave Studio software. For the

designing of rectangular microstrip antenna, the following

relationships are used to calculate the dimensions of

rectangular microstrip patch antenna [3].

1

r 1 r 1 

h 2

reff 

2



2

1 



12

W



Leff  c 2 f0 reff

  reff

 0.3

W 

 0.264

L  0.412

h



  h

reff

 0.258

W 

 0.8

h 

L  Leff  2L

f  1  v0 r 2L r00 2L r

W 1 2 fr 00

2 r 1

Lg  6h  L

Wg  6h W
where, h = substrate thickness L = length of patch
Leff = effective length
W = width of patch c = speed of light f0 = resonant frequency

29

International Conference on Recent Advances and Future Trends in Information Technology (iRAFIT2012) Proceedings published in International Journal of Computer Applications® (IJCA)

r = relative permittivity
reff = effective permittivity
Lg = Length of ground plane
Wg = Width of ground plane
3. DESIGN PARAMETERS
Figure 1(a) and 1(b) show the front view geometry and the structure designed on CST Microwave Studio software of proposed microstrip line fed patch antenna with single band operation for WLAN application. The dimensions and feed point location for proposed antenna have been optimized so as to get the best possible impedance match to the antenna. The following parameters are used for design of proposed antenna.

Figure 6 shows the simulated 3-D radiation pattern at frequency of 5.2 GHz. It shows that proposed antenna radiates in omni-directional nature. It also shows that the directivity of proposed antenna is 6.394 dBi at resonating frequency of 5.2 GHz.

Figure 2: Simulated Return Loss Curve

Figure 1 (a): Front view geometry of proposed antenna

Figure 1 (b): Designed structure on CST microwave studio
Design frequency = 5.21 GHz Substrate permittivity = 4.4 Thickness of substrate = 1.6 mm Length of patch (L) = 12.636 mm Width of patch (W) = 25.8 mm Length of Ground (Lg) = 22.83 mm Width of Ground (Wg) = 27.154 mm
4. SIMULATED RESULTS
The parameters for the designed antenna were calculated
and the simulated return loss results are shown in Figure 2. The bandwidth at the resonating frequency 5.21 GHz is 190 MHz with the corresponding value of return loss as -47 dB. The bandwidth of 190 MHz is achieved as shown in Figure 3. The antenna covers the WLAN standard IEEE 802.11 (5.2 GHz band). The achieved value of return loss is small enough and frequency is closed enough to the specified frequency band for 5.2 GHz WLAN applications. The return loss value i.e. -47 dB suggests that there is good matching at the frequency point below the -10 dB region. The achieved antenna impedance is 50.89 ohm as shown in Figure 4, which is very close to the required impedance of 50 ohm. The VSWR ratio is 1:1.032 is shown in Figure 5, which should lie in between 1 and 2.

Figure 3: Bandwidth plot
Figure 4: Curve showing antenna characteristic impedance
Figure 7(a) and 7(b) show the Elevation (E-plane) and Azimuthal (H-plane) radiation patterns at the resonating frequency of 5.2 GHz. The maximum achievable gain over the entire frequency band is 7.898 dB.
30

International Conference on Recent Advances and Future Trends in Information Technology (iRAFIT2012) Proceedings published in International Journal of Computer Applications® (IJCA)

Figure 5: VSWR curve

Figure 6: 3-D Radiation Pattern of Patch antenna at 5.2 GHz
Figure 7 (a): Elevation radiation pattern of proposed patch antenna at 5.2 GHz

5. CONCLUSION
A microstrip line fed single frequency microstrip patch antenna has been designed and simulated using CST Microwave Studio software. This is operating in the frequency band of 5.108 GHz – 5.298 GHz covering 5.2 GHz WLAN communication standard. The simulated impedance bandwidth at the 5.2 GHz band is around 190 MHz with the corresponding value of return loss as -47 dB which is small enough and frequency is closed enough to the specified frequency band feasible for WLAN application. This return loss value i.e. -47 dB suggests that there is good impedance matching at the frequency point below the -10 dB region. An omni-directional radiation pattern result has been obtained which seems to be adequate for the envisaged applications. The antenna also shows quite good gain of 6.948 dB at 5.2 GHz frequency band of wireless communication with a good impedance matching of 50.89 ohm. However, the size of the microstrip antenna, reported here, is not very small. Cutting inclined slots on the patch, the size of the microstrip antenna may be reduced, also the bandwidth may be enhanced. Work is going on to achieve even better results with good axial ratio over a wide bandwidth.
6. ACKNOWLEDGEMENTS
We are grateful to referees for their valuable comments.
7. REFRENCES
[1]. P. Pigin, 2006 “Emerging mobile WiMax antenna technologies”, IET Communication Engineer.
[2]. R.Garg, P.Bhartia, I.Bahl, A.Itipiboon, 2000. “Microstrip antenna design handbook”, Artech House, Boston – London.
[3]. James,J.R., and P.S.Hall, 1989. “Handbook of Microstrip Antennas”, Vol.1, London: Peter Peregrinus Ltd.
[4]. Z. I. Dafalla, W. T. Y. Kuan, A. M. Abdel Rahman, and S. C. Sudhakar, 2004 ‟‟Design of rectangular microstrip patch antenna at 1GHz‟‟, Multimedia University, Faculty of engineering and technology, Melaka, Malaysia, „‟RF and Microwave Conference, October 5‐6‟‟. Malaysia.

Figure 7 (b): Azimuthal radiation pattern of proposed patch antenna at 5.2 GHz

31

Preparing to load PDF file. please wait...

0 of 0
100%
Proceedings published in International Journal of Computer